The Impact of Exercise on Brain Function
To answer this question clearly, we can first take a look at the relationship between exercise and our brains.
We Have Been Walking
We humans have come a long way and also come very far. When the tropical rainforest where our ancestors lived began to shrink and the local food supply was insufficient, they were forced to start migrating around to find more green plants and pick more wild fruits. At that time, they and other animals There is no difference, they all rely on the sky for food, their brains are not as smart as we are now, and their limbs were not more developed than other animals. It can be said that it was not very outstanding in the biological world at that time. As described in “Let the Brain Be Free”, our ancestors did not have a lot of complex skills to climb up and down in the three-dimensional tree environment. Facing the increasingly arid climate, they could only start to climb up and down in the arid two-dimensional environment. Walking around the savannah in search of food.
According to the famous anthropologist Richard Wrangham, adult men at that time walked about 10 to 20 kilometers a day, and women walked about half that distance.
Human ancestors faced many problems in the process of constant movement. Sometimes it might be a food shortage, sometimes it might be a matter of life and death. It can be said that our brains evolved while constantly solving these problems.
- “Scientists estimate that humans covered 12 miles of ground per day at the time, which means our amazing brains evolved while humans were solving problems, not just lounging around.” — “Set Your Brain Free” by John Medina
In “A Brief History of Humankind”, we know that about 2 million years ago, our direct ancestors, Homo sapiens, began to migrate outward at a rate of about 25 miles per year to expand their territory. They appeared in East Africa about 100,000 years ago. About 70,000 years ago, Homo sapiens began to attack from Africa and migrate to other areas. Soon their territory reached Europe and East Asia. About 45,000 years ago, our ancestors arrived The Australian continent, which had never been inhabited by humans, arrived in Argentina about 12,000 years ago.
Our ancestors, Homo sapiens, crossed rivers, deserts, jungles, and mountains without the help of maps and tools; they built ocean-going ships without wheels or metallurgical technology and then used the most primitive Navigation skills, a bumpy journey across the Pacific Ocean. Considering the productivity and production tools of our ancestors as well as the environment they lived in at that time, it can be said that this is a very remarkable feat.
We can’t imagine how many novel things they encountered, how many injuries they suffered, and all kinds of strange diseases they encountered along the way. Along the way, they had no other special tools to help them get out of their old homes and move toward new territories. Ability to exercise by walking or running.
We have reason to believe that the evolution of our human brains occurs in the constant movement of humans.
- “Given our relative vulnerability among the entire animal kingdom (we don’t even have enough body hair to withstand a slight chill at night), these data tell us that humans grew up to extremely tall stature, otherwise we simply wouldn’t have survived. These data also tell us that the human brain has become the most powerful brain in the world in eternal motion.” – John Medina, “Let the Brain Be Free”
Why Can Exercise Transform the Brain?
Why can exercise transform the brain? Before introducing why exercise can transform the brain, we first introduce a study from the California Department of Education (CDE). CDE links standardized test scores for learning outcomes with recorded scores on the Fitness Gram. The physical fitness test includes six aspects: aerobic capacity, body fat ratio, abdominal strength and endurance, trunk strength and flexibility, upper body strength, and overall flexibility. If students meet the minimum requirements in a certain aspect, they will receive 1 point. Therefore, the full score of the physical fitness test is 6 points. It is worth noting that it does not assess a student’s physical fitness, but only whether he meets the requirements in each aspect. In other words, it’s a pass-or-fail test.
Over the past five years, CDE research has shown that students with good physical fitness scores also perform well on exams.
Psychophysiologist Charles Hillman conducted a personal version of the CDE study on 216 3rd to 5th-grade students. The results also found a correlation between physical fitness and learning and found that there was a relationship between body mass index and aerobic fitness. The correlation between academic performance is particularly obvious.
In cognitive ability tests, students wear a swim cap-like device with embedded electrodes that measure brain wave activity. Electroencephalography (EEG) shows that students with good physical fitness have more active brains. This result suggests that our brains engage more neurons in our attention when completing a given task.
The above experiments and results come from “Exercise Transforms the Brain”.
Our brain is composed of 100 billion neurons (nerve cells) of different types. The transmission of information between neurons is completed through hundreds of different types of chemicals. Neurons control us by transmitting information between them. Everyone’s thoughts and actions.
The information transmission of neurons in our brain has its working mechanism. They rely on this mechanism to continuously transmit electrical signals from the axons of neurons to synapses, and then pass through the neurons through neurotransmitters. gap passed to the dendrite of the next neuron.
“Neurons work by conducting electrical signals along the neuron’s outward branches (axons), all the way to the synapse. There, neurotransmitters carry chemical signals across the synaptic cleft. At the other end, in the branches Neurotransmitters on the dendrites or receptors of the next neuron bind to specific receptors there, like a key in a lock, opening the synaptic cleft. Channels in the cell membrane of that neuron convert this signal to electric current. If the cumulative current load on a neuron exceeds a certain threshold, it sends a bundle of nerve impulses down its axon, which then goes out and repeats the entire process.” — John Medina, “Free Your Brain”
Common neurotransmitters include:
- Glutamate stimulates nerve impulses, initiating a cascade of signal transmission; gamma-aminobutyric acid (GABA) inhibits impulses.
- Serotonin, an inhibitory neurotransmitter, was first discovered in serum and is found in high levels in the cerebral cortex and nerve synapses. Serotonin enhances memory and protects neurons from damage by “excitatory neurotoxins.”
- Norepinephrine is a neurotransmitter that scientists believe enhances signals that influence attention, cognition, motivation, and arousal.
- Dopamine is considered a neurotransmitter that affects learning ability, reward system (satisfaction), attention, and movement, and sometimes it has opposite effects in different parts of the brain. Methylphenidate reduces attention deficit hyperactivity disorder (ADHD) by increasing the sedating dopamine.
In “Exercise Transforms the Brain,” the author gives an example of running 1,600 meters long-distance and taking a very small dose of Prozac (a serotonin drug) and a very small dose of Ritalin (which increases the sedative effect of dopamine). It has the same effect on reducing attention deficit hyperactivity disorder (ADHD), which suggests that exercise, like these drugs, can increase neurotransmitter levels. In other words, exercise brings balance between neurotransmitters and other chemicals in the brain.
There is also a family of protein molecules broadly called factors that, like neurotransmitters, change the previous interconnections between nerve cells, such as brain-derived neurotrophic factor (BDNF). Neurotransmitters carry out information transmission, while neurotrophins like BDNF build and maintain nerve cell circuits, the basic structure of the brain itself.
BDNF and exercise produce synchronous changes, that is, exercise can increase BDNF levels.
Karl Cotman, director of the Institute for Brain Aging and Dementia at the University of California, Irvine, designed an experiment.
In this experiment, the experimental animals, mice, were divided into four groups: one group ran for two nights, the other two groups ran for four and seven nights respectively, and a control group that did not participate in wheel running. In the experiment, the researchers first injected mice with a molecule that can bind to BDNF in the brain and then scanned them. The results showed that the increase in BDNF in the brains of the mice in the exercise group was greater than that in the control group, and the longer each mouse ran, the more BDNF increased in the brain.
Other scientists such as Aero Castellon and Susan Patterson of Columbia University’s Kandel Laboratory discovered that by letting mice learn to stimulate long-term potentiation (LTP), BDNF in their brains The level will increase accordingly. Researchers observed the brains of mice and found that mice lacking BDNF lost the ability to LTP; conversely, directly injecting BDNF into the brains of mice could promote LTP. Neurosurgeon Gomez Pinilla confirmed that if BDNF in the brain of mice is not able to work properly, it will be difficult for mice in the pool to find a hidden underwater platform and escape.
Conclusion
The conclusions of these experiments provide reliable evidence that exercise helps the brain learn. In other words, these experiments confirm that exercise helps increase levels of BDNF, which is important not only for nerve cell survival but also for nerve cell growth (sending new branches). So Kottman concluded that “one of the most significant features of exercise is that it can improve learning efficiency.”